1. Field of the Invention
This invention relates to a seal arrangement around an insert in a plastic molding process such as injection molding, to prevent flash from escaping from the cavity at the insert location.
In producing plastic parts having metal inserts such as electrical connectors or plugs which project from the plastic part, a very tight fit of the insert in the cavity is desired so that flash cannot escape. Flash around the insert is cosmetically undesirable, and the flash may also interfere with subsequent assembly operations involving the part.
One solution is to allow the flash to be produced, but to then remove that flash in a subsequent operation. However, especially for parts which may be worth only one or two dollars each, the labour costs involved in removing the flash are proportionately exorbitant. The best solution is to avoid the production of the flash in the first place.
2. Description of the Prior Art
In the prior art, the most common means of avoiding the production of flash has been to machine the insert opening in the cavity to very close tolerances (e.g. plus or minus .001 inch). Even so, flash frequently escapes due to the ordinary production tolerances found in the inserts themselves. There is a need for an improved means of preventing the escape of flash.